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## Installation and Upgrade of LMDE (Linux Mint DEbian)

Hello there!

Yesterday I installed Linux Mint DEbian (or LMDE) on one of my machines. If you check the Blog Website, the last released version was the 201303. From last March until now, a lot of packages have been updated, therefore it is customary to update (and upgrade) the system right after the installation.

Nonetheless, if you do that… things will go completely wrong.

Fortunately, I found this post on the official Linux Mint forum. Thus I post the steps I follow 1

# apt-get update

if the Installed and Candidate packages are not the same, then install the new one… and then proceed to the upgrade of the system,

Cheers.

#### Footnotes:

1You will need root power, or using the sudo command at the beginning of each line

## Emacs Tip: Using Macros

Yesterday I started to edit an old $\LaTeX$  file, and it happened that in my set of definitions I changed a bold math-operator with no arguments \df, by a math-operator with one argument (which happens to by the following word) \de{#1}.

## The problem

The issue now is that I should go all over the text finding the \df command and replaced by \de{#1}. But note that the is a delimiter with the curly bracket!

## The solution

A while ago I found a page called , and I learn about emacs’ macro, i.e., a set of rules you define and then can be applied recursively.

### How is it done?

A short explanation is given at .

In my case I follow that rules below:

• Press F3 to start recording the macro.
• Look for the initial command and change it by the other using M-% \df (press enter) \de{ (press enter)
• Move the cursor forward until the end of the next word using the command M-f
• In that cursor place close the curly bracket }
• Finish the recording of the macro by pressing F4.

Finally, to apply the macro use F4 to apply it once, M-4 F4 to apply it 4 times or M-0 F4 to apply it until it fails.

## LaTeX tip: \allowdisplaybreaks

A quick tip: When writing a long aligned equation, use the following command, \allowdisplaybreaks in the preamble.

## Example

\documentclass{report}
\usepackage{amsmath}
\usepackage{lipsum}
\allowdisplaybreaks

\begin{document}
\lipsum[1-4]
\begin{align*}
Ffffffffffffffffffffffffffffff &= \partial_t(p)\\
&= \partial_t(m v)\\
&= m a\\
&= m \dot{v}\\
&= m \ddot{x}\\
&= \partial_t(p)\
&= \partial_t(m v)\\
&= m a\\
&= m \dot{v}\\
&= m \ddot{x}
\end{align*}
\end{document}

After installing CalcHEP (see this post), oen should go to the working directory created by CalcHEP and running the program,

$cd ~/Documents/WorkCalcHEP$ ./calchep

Calling the program.

Then the CalcHEP shell will appear, and you can choose your model (in future posts I’ll tell you the easiest way to create and import models)

List of Models included in CalcHEP

Once you have picked a model, you can enter a process

Possibilities after choosing the model

The list of particles in the model you have chosen is shown, and you can write the process you want to study. Note that diagrams with certain particles can be excluded, but in this example I didn’t.

Entering the process on the shell

Resulting in,

Result of the entered (sub)process

CalcHEP can draw the Feynman diagrams of a certain (sub)process,

Feynman diagrams of the subprocess

and after squaring the amplitude,

Squaring the (sub)process amplitude

you can see the “squared Feynman diagrams” 🙂 Cool, Isn’t it?

Squared Feynman diagrams of the (sub)process

In a future post I shall write about the numerical integration, or the possibility of exporting plots and Feynman diagrams to LaTeX 😀

Cheers.